He is showing you the difference between committing a sin, and being a sinner.
See, if you are born again, then you are become "the righteousness of GOD.......in Christ"..
So, you are no longer a sinner, but you can mess up.
Paul calls this........"committing a work of the Flesh".
whereas, the UNBELIEVERS, are SINNERS, because Christ has not paid for their sin.
This means they are sinners, who are sinning.